(1) Complete the isolation and characterization of the dorsal protein-I (DP-I) gene. (a) A cDNA library prepared from rat dorsal prostate mRNA will be screened for DP-I cDNA by hybrid selection for translation. (b) DP-I mRNA, enriched by oligo-dT cellulose chromatography and sucrose gradient centrifugation, will be cloned into the phage expression vector lambda qt 11. Plaques containing recombinants will be screened by blotting proteins onto nitrocellulose and detection of DP-I with purified DP-I antibody and (125I)-protein A (staphlococcus aureus). (c) DP-I cDNA will be sequenced using the method of Maxam and Gilbert. (2) DNA from tumors of the rat dorsal prostate (R-3327H and Nobel) will be compared with normal prostate DNA by restriction enzyme digestions and Southern hybridization using DP-I cDNA as probe. mRNA from the tumors will also be probed with labeled DP-I cDNA in comparison with mRNA from normal dorsal prostate. (3) Genomic libraries of normal dorsal prostate and dorsal prostate tumor DNA will be screened with labeled DP-I cDNA to isolate the cellular DP-I genes and flanking DNA. (4) Cloned viral oncogenes have been obtained from NCI and the Department of Tumor Virology at M.D. Anderson Hospital. These include: v-fes, v-fms, c-myc and v-myc, v-myb, v-ras, v-mos and c-mos. Additional clones will be obtained as they become available. Our plan is to screen mRNA from normal and neoplastic prostate using the labeled oncogenes as hybridization probes. If an oncogene message is increased in tumor, the androgen dependence of message transcription will be examined.